The goal of the MacCHESS Research Resource is to support macromolecular crystallography at the Cornell High Energy Synchrotron Source (CHESS). This will be accomplished by developing and providing specialized instrumentation for crystallographic studies by our national user community and by performing core research that advances the frontiers of synchrotron radiation research. We will continue to provide service to the macromolecular crystallography community with special emphasis on monochromatic oscillation data collection and MAD phasing techniques. The facilities at CHESS should be particularly useful for small crystals, crystals with large unit cells, weakly diffracting crystals and crystals susceptible to radiation damage. Central to our goal is the development of more user friendly hardware, software and operational procedures that will make trips to CHESS more productive. MacCHESS will support macromolecular crystallography on beamlines A-1 (monochromatic oscillation data), B-2 (Laue diffraction), F-1 (monochromatic oscillation data with biohazard containment facilities) and F-2 (MAD phasing). Access to these experimental stations will be based on the CHESS peer- reviewed proposal system. Future core research will include establishment of a centralized data reduction facility, implementation of CCD-based X-ray detectors, construction of apparatus for MAD phasing on station F-2, development of microfocusing optics for X-ray diffraction studies of microcrystals, upgrade of station A-1 to take advantage of the new A line wiggler, implementation of low-temperature techniques, investigation of high energy X-ray diffraction, general optics development and undulator experimentation. In addition, we will continue to develop software for data collection and analysis and to make the software more user friendly. MacCHESS will provide trained staff to assist users in setting up beamlines, designing experiments and processing X-ray diffraction data. CCD-detector development will be supplemented by acquisition of additional image plate scanners and additional electronic and computing equipment will be purchased to refurbish a synchrotron radiation laboratory that has been productive for more than ten years. All of these developments will bring nearer the goal of rapid visualization of macromolecular structure. Finally we will continue to provide training and dissemination through maintenance of operation manuals, preparation of a MacChess brochure, on-site instruction, organization of workshops, presentations at meetings, presentation of invited seminars and production of training videos for CHESS facilities and low temperature techniques.